Certain types of semiconductor devices like semiconductor memories comprise structure elements or patterned layers that are periodic at least in one dimension. Word lines and bit lines, for example, are often arranged along straight lines running parallel to one another. The width of the lines and the distance between neighboring lines are constant all over the device. Thus, the succession of the lines in one direction is periodic, preferably of minimal dimensions, which enables to realize a memory cell array of minimal area. The dimensions of the lines and their interspaces are continually repeated in the direction of the periodic succession. The length of one of these periods is called the pitch of the pattern.
The value of the pitch is restricted by the production technology that is applied to structure the periodic pattern. Some limitations are due to the mask technique that is employed in the structuring process. In the usual etching processes using masks, there are lower limits to the dimensions that can be obtained. The further miniaturization of the devices, on the other hand, necessitates the provision of production methods by which smaller pitches can be realized. These methods are only applicable if the structures that are produced are sufficiently precise to meet the requirements of the device performance.